Greetings! It’s been awhile since I’ve been here but I could use some help. Over the years, my 4120 has been invaluable and a steady workhorse. However, it has one repeating problem that I’d like to learn to fix myself. On two separate occasions over the past 16 years, I’ve taken it to a dealer to fix and apparently the return fuel line gets clogged or dirty and needs to be cleaned out. My problem (or one of them) is that I’m not a mechanic and while I do all the routine stuff, I don’t know how to find the return fuel line so that I can clean it. I’ve searched online for a diagram or service manual and have come up empty. Anyone out there who can explain where to find the line and fitting I need to clean? Thanks!